"Duration" is how many turns the Buff-Debuff will be in effect for once applied.
"Targets" is the number of entities that the item can be used on at one time.
The left-hand side of the stat inputs determine the base effect of the buff (for positive numbers) or
debuff (negative numbers). The right-hand side inputs will be added to the base effect each turn. So for example
a "Strength Potion" with duration 3 might start with a base increase of 10 Physical Attack. If it has a Growth of
-2 for Physical Attack then the buff will contribute 8 Physical Attack after the first turn, 6 after the second turn,
and be removed after the third turn.